If $a+b+c=9$ and $a b+b c+c a=-22$, then the value of $a^3+b^3+c^3-3 a b c$ is:
Answer & explanation
Correct answer: option 2
If x + y = n
then, $x^3 + y^3$ = n3 - 3 × n × xy
If $a+b+c=9$
$a b+b c+c a=-22$
Then the value of $a^3+b^3+c^3-3 a b c$= ?
If the number of equations are less than the number of variables then we can put the extra variables according to our choice =
So here two equations given and three variables are present so put c = 0
If $a+b=9$
$a b=-22$
Then the value of $a^3+b^3$= 93 - 3 × 9 × -22
Then the value of $a^3+b^3$= 1323